This invention relates to a cable grommet system, particularly for use in connection with data centers, offices and the like to accommodate the passage of cables from one side to another of a floor, cabinet, rack, or other enclosure serving as a containment between two areas, particularly where the areas are under unequal air pressure, such as for conditioned air (heating or cooling) under positive pressure. The term “cable”, as used herein, refers not only to flexible electrical wires and cables but also to rigid elements, such as pipes, conduits and the like that may be extended through openings in floor or other panels, especially where it is desired to restrict the flow of air through such openings.
In data centers and the like, large numbers of computer servers typically are arranged in a compact configuration of cabinets or racks. Large numbers of the cabinets or racks may be housed in a common area, to facilitate access to the servers by technicians for wiring and rewiring, servicing, etc. Commonly in such installations, a raised floor structure is provided, creating a space under the floor for the passage of the necessary wiring and cabling to power the servers and to transmit the input and output signals therefrom. The wiring and cabling for a particular server rack is extended through the space below the floor, and is passed upward through the floor to enable connection with the servers, typically, but not necessarily, at the back of the rack.
Modern high speed servers generate significant heat during operation, and this heat must be dissipated effectively in order to avoid damage to and/or malfunction of the servers. Accordingly, it is customary to provide an air conditioned environment for the servers, typically by providing the conditioned air under pressure (e.g., 0.1 inch of water) in the space provided underneath the raised flooring. Outlets for the conditioned air are located at each of the server cabinets or racks, typically at the front thereof, such that the cooled air may flow upward along the front of the cabinet rack and be drawn into and passed through the individual servers from front to back.
Openings provided in the flooring for the passage of cable can result in the undesired flow of some of the cooling air through the cable openings. The leakage of cooling air through such openings can represent a significant economic loss, because cooling air that simply mingles with the general atmosphere of the data center, and does not flow properly to intake openings at the front of the servers, does not function effectively to cool the servers and its cooling effort is simply lost. In a typical large data center, there can be large numbers of such cable openings (for example, as many as sixty openings per thousand square feet of floor space). Collectively, this can represent a significant loss of cooling capacity, if conditioned air is allowed to escape through these openings.
Heretofore, various efforts have been made to seal off these openings. However, because the cabling of data centers is very dynamic, in the sense that the server setups, and the cabling for servicing them, are constantly changing, many sealing concepts that would otherwise be suitable for wiring and cabling are not suitable for use in dynamically changing data centers and the like.
A significant advance in the design of cable grommets for data centers and the like is reflected in the Sempliner et al. U.S. Pat. No. 6,632,999, which discloses and claims a particularly advantageous form of cable grommet comprising a frame, suitable for fitting into a cable opening in a floor, cabinet or other pressurized space, and provided with a unique arrangement of one or more brush-like sealing elements comprising a large plurality of filamentary elements forming a substantial seal of the opening in the grommet frame. The arrangement enables cables and the like to be easily passed through the filament-sealed opening, such that frequent wiring and rewiring is greatly facilitated. After the wires and cables are passed through the grommet opening, the opening is automatically effectively sealed by the multitude of filaments which deflect and close around the cable elements. The cable grommet of the Sempliner et al. '999 patent has been very successful commercially and has achieved very significant economies in the operation of data centers, and even in less densely wired areas, such as offices, for example.